Propeller for vessels



(No Model.)

L. L. LEATHERS. PROPELLER FOR VESSELS.

No. 537,612, Patented Apr. 16, 189'5'.

ATEENT Prion.

LEVI L. LEATHERS, OF ST. ALBANS, MAINE.

PROPELLER FOR VESSELS.

SPECIFICATION forming part of Letters Patent No. 537,612, dated April 16, 1895.

Application filed June 25, 1894- Serial No. 515,686- (No model.)

To all whom, it may concern:

Be it known that I, Lnvl L. LEATHERS, a citizen of the United States, residing at St. Albans, in the county of Somerset and State of Maine, have invented certain new and useful Improvementsin Propellers for Boats; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to a screw propeller .wherein a shaft carrying a propeller which operates in one direction, is surrounded by a hollow shaft carrying another propeller which operates in the opposite direction in the same axial line, and it consists, first, of two propellers of different relative sizes operating in opposite directions, one being a right hand and the other a left hand Wheel, the larger wheel being arranged in rear of the smaller wheel; secondly, of two rightand left hand wheels of different sizes, the larger wheel be ing arranged in rear of the smaller Wheel and in the same axial line and provided with a fewer number of blades than the smaller wheel and it further consists of an improved straight gearing in combination with a shaft carrying a propeller wheel and a hollow shaft carrying a smaller propeller wheel forward of the first mentioned wheel and it also consists in certain other novel constructions and combinations as hereinafter described and claimed.

In the accompanying drawings, Figure 1. is a side elevation of the propeller wheels, seat box and gearing for transferring motion to the shafts and propeller Wheels carried thereby. Fig. 2. is an end View of the propeller wheels looking forward, and Fig. 3. is a transverse vertical section through the propeller shafts and looking toward the propellers. Fig. at. is a side view of a portion of the stern of a floating craft, showing propellers applied to the same and a coarse screen or wire frame guard partially inclosing the propeller wheels, and Fig. 5. is a vertical transverse section through the gears and operating shafts.

A in the drawings, represents myimproved propeller, in which B represents an inner shaft carrying a propeller wheel 0, and D is a hollow surrounding shaft carrying a smaller propeller wheel E in the same axial line with the wheel 0 and provided with a larger number of'blades, all arranged and operating as will now be fully set forth.

The inner shaft B is passed longitudinally through the stern of the boat, one of its ends extending outward and having keyed or otherwise suitably secured to it the propeller wheelO and its other end connected with a suitable operating means not shown. The hollow shaft D surrounds the shaft B a considerable portion of its length and has keyed or otherwise suitably secured to it at its rear or outer end the smaller propeller wheel E and at its opposite or inner end is provided with a large spur wheel I which meshes with and is actuated by an internally toothed'gear wheel I secured on the inner end of the shaftB, through a small pinion wheel I interposed between the teeth of the gear Wheel I and the spur wheel I as shown. A sleeve or collar (Z is interposed between the hubs of the propeller wheels to keep said Wheels the proper distance apart. When power is applied to the inner shaft B it will cause said shaft and the propeller Wheel 0 carried thereby to be revolved in one direction and the hollow surrounding shaft D and the propeller wheel E carried thereby to be re volved in the opposite direction and the lateral disturbance of the water is thereby greatly overcome and a greater propelling power secured.

The propeller wheel E which is forward of the propeller wheel G is of less diameter than the said wheel 0 and is provided with a larger number of blades or wings than the wheel G and inclined in opposite directions. I have shown the forward or smaller propeller wheel E provided with four blades or wings and the larger or rear propeller wheel provided with three blades or wings, but the number may be proportionately varied. I also secure the front propeller wheel E on the hollowshaft D in such a manner that a portion of the blades of the said wheel fall in axial line with or cover the space between the wings or blades of the rear propeller wheel 0, as I have found by practical tests that the best results are socured from this arrangement and construction. I have experimented with the propeller with the same number of blades or wings on both wheels and both wheels the same size,

ICO

with four blades the same size in both wheels and failed to get as much power and as good results as with the construction and arrangement shown and described, as by this construction and arrangement no whirlpool is formed, the smaller wheel throwing the water into a funnel shape and keeping the air away from the wheel, thus preventing chopping the water as is the case where air has access to the wheel. I also find that the greater power can be obtained by having one wheel smaller than the other, the smaller wheel being arranged forward of the larger wheel and provided with a larger number of blades.

I do not Wish to limit my inventionjo the number of propeller blades shown on the respective wheels as they can be proportionately varied.

J represents a coarse screen or wire frame which is attached to the stern of the boat and partially incloses about one fourth of the circumference of the smaller or forward wheel and extends to about midway the width of the wheel. The object of this screen or wire frame is to assist in destroying the whirlpool produced by propellers in common use.

I have found by experimenting that if the larger or rear propeller runs as fast or faster than the smaller or forward wheel, it will throw the water backward so rapidly that a great suction of the Water is caused which passes through the smaller or forward wheel causing it to have less power than it would have if said smaller or forward wheel was revolved very rapidly. To secure this object I construct the gearing as shown and described, and at the same time I secure a powerful, straight gear movement, all bevel gears being dispensed with.

What I claim as my invention is 1. A propeller for boats, comprising two bladed wheels of difierent relative diameters with respect to each other, arranged in the same axial line and adapted to be operated in opposite directions, the smaller wheel being arranged in front of the larger wheel and provided with a greater number of blades than the larger wheel, substantially as described.

2. A propeller for boats, comprising two bladed wheels of difierent relative diameters with respect to each other, arranged in the same axial line and adapted to be operated in opposite directions, the smaller wheel being arranged on a hollow shaft in front of the larger wheel and provided with a greater nu mber of blades than said larger wheel, a shaft to which the rear or larger propeller is secured provided with an internally toothed gear wheel, a spur wheel on the hollow shaft and a supported pinion interposed between the spur and gear Wheels, substantially as described.

In testimony whereof I hereunto affix my signature in presence of two witnesses.

LEVI L. LEATHERS.

Witnesses:

N. B. TURNER, LOREN LEATHERS. 

